The present invention relates to the design, development and malfunction investigations of the tube-fired munitions. More particularly, the invention herein relates to a low cost system for the telemetering of delayed high-G in-bore information.
In the past, certain techniques for acquiring in-bore information have not been completely satisfactory in furnishing a complete environmental profile of a shell while in-bore. These techniques have included:
(1) Hardwiring of the shell transducer directly to recording equipment located outside the gun tube. This technique suffered from the problem of wire breakage at higher firing zones.
(2) Radio frequency transmission of in-bore data out of the gun tube to the ground station recording equipment. This has often been less than optimum due to blow-by gases attenuating the R.F. signal, reflections, and cancellations in the gun tube.
(3) Laser beam transmission of in-bore data out of the gun tube. This has not been successful due to difficult alignment problems of transmitter and receiver, and obscuration of the light beam by blow-by gases.
The aforementioned radio frequency technique utilized a particular charge-coupled analog delayed device (CCD) to delay in-bore information until the projectile clears the gun barrel and the ionized cloud.
The total cost of in-bore telemeter components in the present system would be less than half of the component cost of telemeters using charge-coupled devices to achieve the analog delay.
The present invention eliminates the above shortcomings in the prior art and, in so doing, presents a system which is both more effective and more economical than any previously known. The significant innovative areas of the invention disclosed herein include:
(a) The delay of analog signals achieved by means of Delta-Modulation (DM) and binary shift registers (S/R). This delay circuitry makes extensive use of digital logic components which can be fabricated and packaged at low cost.
(b) This technique utilizes digital logic components which can be operated over a wider temperature range than CCD devices. Temperature compensation and bias sources are not required, as in the case with CCD devices.
(c) Where a requirement to telemeter several moderate frequency response channels exists, a time-division multiplexing technique may be used to reduce overall hardware complexity with attendant cost saving.
(d) The component cost of the system is estimated to be one-half the cost of a CCD analog delay circuit for applications where moderate channel bandwidth is acceptable.
(e) A binary data recirculation technique for the simplification of delay circuitry and for improving the reliability of received in-bore telemetry data is easily implemented. This will reduce the required duration of time delay no longer than the duration of in-bore events.